1. Field of the Invention
The present invention relates to the microbiological industry, and specifically to a method for producing an L-amino acid using a bacterium of the Enterobacteriaceae family which has been modified to attenuate expression of the ybiV gene.
2. Brief Description of the Related Art
The ybiV gene in Escherichia coli encodes the YbiV protein, a hypothetical protein with sequence homology to the haloacid dehalogenase (HAD) superfamily of proteins. Although numerous members of this family have been identified, the functions of few are known. Using the crystal structure, sequence analysis, and biochemical assays, YbiV has been characterized as a HAD phosphatase. The crystal structure of YbiV reveals a two-domain protein, one domain with the characteristic HAD hydrolase fold, and the other domain with an inserted alpha/beta fold. In order to understand the mechanism, the structure of YbiV complexed with beryllofluoride (BeF3−) and aluminum trifluoride (AlF3) has been determined. This structure mimics the phosphorylated intermediate and transition state for hydrolysis, respectively, similar to other HAD phosphatases. Analysis of the structures reveals the substrate-binding cavity, which is hydrophilic in nature. Both structure and sequence homology indicate that YbiV may be a sugar phosphatase, and this indication is supported by biochemical assays that measured the release of free phosphate on a number of sugar-like substrates (Roberts, A. et al. YbiV from Escherichia coli K12 is a HAD phosphatase. Proteins, 2005, 58(4):790-801).
But currently, there have been no reports of inactivating the ybiV gene for the purpose of producing L-amino acids.